Standing wave pump

ABSTRACT

An efficient fluid pump which has a chamber for receiving the fluid to be pumped and a transducer for establishing a travelling wave in the fluid. The length of the chamber and the frequency of the transducer are adjusted so that a standing wave pattern is set up in the fluid having one or more pressure nodes and one or more pressure antinodes in it. At least one entrance port is provided in the chamber at the pressure nodes and at least one exit port is provided in the chamber at the pressure antinodes so that fluid will be drawn into the cylinder at the pressure node and will be forced out of the cylinder at the pressure antinode to achieve a pumping action.

United States Patent [191 Mandroian STANDING WAVE PUMP [75] Inventor:Harold Mandrolan, La Canada,

- Calif.

[73] Assignee: Atek Industries, Inc., North Hollywood, Calif.

22 Filed: July 12, 1971 21 Appl. No.: 161,656

m1 3,743,446 July 3,1973

3,657,930 4/1972 Jacobson 417/322 Primary Examiner-William L. FreehAssistan! Examiner-John T. Winburn Attorney-Frederic P. Smith 57ABSTRACT An efficient fluid pump which has a chamber for receiving thefluid to be pumped and a transducer for establishing a travelling wavein the fluid. The length of the chamber and the frequency of thetransducer are adjusted so that a standing wave pattern is set up in thefluid having one or more pressure nodes and one or more pressureantinodes in it. At least one entrance port is provided in the chamberat the pressure nodes and at least one exit port is provided in thechamber at the pressure antinodes so that fluid will be drawn into thecylinder at the pressure node and will be forced out of the cylinder atthe pressure antinode to achieve a pumping action.

8 Claims, 5 Drawing Figures I5 42 44 JJQQOLD Madame/AIM I INVENTOR.

BY MW BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to apparatus for'pumping fluids.

2. Description of the Prior Art The art of pumping fluids so that theymay be transported from one place to another is extremely old, startingwith such pumping devices as the water wheel and the Archimedes screw.More recently there have been developed reciprocating pumps of the typecomprising an enclosure or chamber communicating through intake valveswith a source of fluid under an initial pressure and through deliveryvalves with a space constituting a receiver for a fluid under a finalpressure, the chamber including a movable wall to which a reciprocatingmovement is imparted to expand the capacity of it to fill it through theintake valves and then to contract the capacity and to evacuate itthrough the delivery valves. Many other variations on this technique ofproviding a chamber which is expanded to receive fluid and thencontracted to force it out through the delivery valves have beendevised, such as providing the pumping action by means of a flexiblemembrane to change the configuration of the chamber, a flexible tubewhich allows the fluid to enter and then squeezes it out, and atwo-chamber system separated by a diaphragm in which an actuating fluidin the first chamber means causes the diaphragm to periodically pulsateand to displace a portion of the actuated fluid from the second chambermeans. In a somewhat different form of pumping device, a diaphragm isactuated to cause a flow of fluid to be pumped across the throat of anorifice and thus to establish a zone of low pressure; due to thisventuri effect, a fluid is pumped through the throat into the main bodyof the system and then is ultimately forced out of the system to achievea pumping action.

As can be seen from the construction and operation of these prior artdevices, these devices are subject to mechanical failure and fatiguewhere reciprocating pistons and valves or flexible diaphragms are usedto draw fluid into a chamber and to force it out of the chamber andsuffer from a low efficiency due to the amount of power required tooperate the moving pistons, diaphragms and valves to achieve the pumpingaction and due to the presence of the unpumped or residual volume leftin the pumping chamber at the end of the compression stroke. Inaddition, the pump system utilizing the venturi effect necessitates avery fast flow of a large bulk of fluid across the throat in order-toachieve a satisfactory zone of low pressure and thus causes a largeamount of strain and fatigue on the pumping diaphragm and the dampingdiaphragm used in the construction of the pumpgalong with a large amountof power input for a relatively small flow of output fluid.

OBJECTS AND SUMMARY OF THE INVENTION The principal object of the presentinvention is to provide a new and improved pump for pumping fluids whichavoids the pumping deficiencies of the prior art apparatus.

A more specific object of the invention is to provide a pump in whichthe moving elements are not utilized to provide a pumping pressure tothe fluid to be pumped.

Another object of the invention is to provide a pump which has a highefficiency of operation.

A further object of the invention is to provide a pump in which thepumping pressure is provided by a nearly motionless actuating fluid.

In accordance with one embodiment of the present invention, a pump isprovided which has a cylindrical chamber having as one end wall afluctuating diaphragm. The diaphragm is caused to oscillate at apreselected frequency by means of a power supply and driver to set up atravelling wave in the fluid in the chamber. The frequency ofoscillation of the diaphragm and length of the chamber are configuredthat the chamber is a resonant chamber and thus a standing wave is setup in the fluid having a pressure antinode or node at the wall oppositethe diaphragm and a series of pressure nodes and pressure antinodesspaced along the length of the chamber, the particular number dependingupon the length of the chamber and the frequency of vibration of thediaphragm. An entrance port is located in the chamber at one of thepressure nodes and on exit port is located 'in the chamber at one of thepressure antinodes. Due to the pressure differential between thepressure node and the pressure antinode, fluid outside the chamber atthe pressure node will be forced into the chamber and fluid outside thechamber at the pressure antinode will be forced out, thus achieving apumping action.

The novel features of the invention are set forth with particularity inthe appended claims. The invention will best be understood from thefollowing description when read in conjunction with the accompanyingdrawmgs.

BRIEF DESCRIPTION-OF THE DRAWINGS DESCRIPTION OF THE PREFERREDEMBODIMENT In FIGHI, an embodiment of the present invention isillustrated. A chamber 10 is provided which has an entrance port 12 andan exit port 14 whose positions are determined, as explained more fullyhereafter, by the location of the pressure nodes and antinodes of astanding wave generated in the chamber 10. Forming one wall of thechamber 10 is a transducer element 18 comprising a flexible diaphragm 15which has a magnetic slug 16 attached thereto, a coil 20 and a core 22attached to the opposite wall 24 of the transducer 18. The coil 20 ofthe transducer 18 is energized by a driver 26, such as an oscillatingcircuit, which in turn is energized by a power supply 28.

In operation, the driver 26 causes the coil 20 to be cyclicallyenergized at a predetermined frequency and thus causes the diaphragm 15,by means of the coils attraction on the magnetic slug 16, to vibrate atsuch preselected frequency and to cause a travelling wave to begenerated in the fluid in the chamber 10. If the length of the chamberis made to be equal to an integer times the wave length of thetravelling wave in the fluid divided by 4, i.e. n.)t/4, the chamber 10will act as a resonant cavity and will have a standing wave pattern setup in it. As is well known, the wave length of the wave in the fluid isequal to the velocity of the wave in the fluid divided by the frequencyof the wave pattern. Thus if the fluid is water and the diaphragm isexcited by a five thousand cycle signal, the minimum length of thechamber 10, that is the wave length divided by 4, would be 0.246 feetsince the velocity of a 5,000-cycle wave in water under standardconditions is 4,920 feet per second. If the frequency of excitation werereduced to 1,000 cycles per second, then the length of the chamber 10would be 1.23 feet. If, on the other hand, the fluid in the chamber 10were air, then for a 1,000-cycle excitation signal, the minimum lengthof the chamber would be 0.28 feet since the velocity of the wave in airunder standard conditions is 1,130 feet per second.

The placement of the entrance port 12 and the exit port 14 in relationto the operation of the invention is best illustrated with reference toFIG. 2. When the transducer 18 is excited by the driver 26, it causes aninitial wave, shown by the solid line, to travel in the fluid in thechamber 10. When this wave hits the far wall 32 of the chamber 10 it isreflected back, shown by the dashed wave, 180 out of phase with theinitial wave. If the chamber 10 has been configured so as to be anintegral number of quarter wavelengths long, the reflected wave, when itreaches the diaphragm wall 15, will be reflected 180 out of phase andthus coincident with the initial wave. In addition, the reflected wavewill be reinforced by the motion of the diaphragm since it is insynchronization therewith. Thus a standing wave pattern, as shown inFIG. 2, is set up in the chamber 10 which has a displacement node or apressure antinode at the end wall 32, a pressure node or displacementantinode at the diaphragm l5 and a series of such nodes and antinodesbetween the two end walls of the chamber. Since the pressure nodes,indicated by the numeral 36, are points of minimum pressure in thefluid, a series of entrance ports 12, 12', 12" are placed in the wall ofthe chamber 10 at such pressure nodes, while since the pressureantinodes, indicated by the numeral 38, are points of maximum pressurein the fluid, a series of exit ports 14, 14', 14", are placed in thewall of the chamber 10 at such pressure antinodes. Thus, when the fluidin the chamber 10 is excited by the action of the transducer I8-and astanding wave pattern is set up therein consisting of pressure nodes andantinodes, the fluid immediately outside the chamber 10 at the entranceports l2, l2, 12" will be drawn into the chamber 10 and the fluid insidethe chamber 10 at the exit ports I4, 14, 14" will be forced out of thechamber 10 due to the pressure differentials at the pressure nodes andthe pressure antinodes. Thus the apparatus shown in FIGS. 1 and 2produces a pumping action due to the differential pressure in the fluidin the chamber 10.

In FIG. 3 a third embodiment of the invention is shown. In thisembodiment there are two chambers 10 and 10' having entrance ports 12and 12' and exit ports 14 and 14'. The two chambers 10 and 10 areseparated by a transducer 18 excited by driver 26, which transducer 18is in this particular instance shown as a piezoelectric crystal. Uponreceiving alternating voltages from the driver 26, the piezoelectriccrystal alternately expands and contracts to cause standing travellingand then standing waves to exist in the chambers 10 and 10'. As shouldbe noted from FIG. 3, the chambers 10 and 10' are of uneqral length butwith each one being an integral number of quarter wavelengths in overalllength. In this particular embodiment, the piezoelectric crystal is in aloaded condition and acts with greater efficiency to pump the fluid inchambers 10 and 10. In addition, chambers 10 and 10' could originallyhave been formed as a single chamber with the piezoelectric crystalbeing inserted at any point therein to effect a separation of chambers,as long as the length of each of the chambers remains an integral numberof quarter wavelengths in length. The standing wave patterns on eitherside of the transducer 18 may be in phase or out of phase with eachother depending on the operation of the transducer 18.

In FIG. 4 a fourth embodiment of the invention is shown. In thisembodiment one wall of the chamber 10 is formed by the transducer 18supported by awebbing 40 coupled to the outer wall 42 of the chamber 10,while the opposite wall of the chamber 10 is formed by an end plate 44supported by a webbing 46 coupled to the outer wall 42 of the chamber10. The entrance port 12 in this configuration is formed between thetransducer 18 and the outer wall 42 of the chamber 10 and the exit port14 is formed in a similar manner between the end plate 44 and the outerwall 42 of the chamber 10. The electrical coupling between the driver 26and the transducer 18 is achieved through a hollowed out portion of thewebbing 40.

It should be noted that in FIGS. 1 to 3 the transducer need not be adiaphragm or a piezoelectric crystal, but may be a series of magnets orcoils driven to produce a wave in the chamber by magneto hydrodynamicforces and that in such case the end walls could be identical with thetransducer operating through or as a part of the outer wall 42 of thechamber 10. Thus the fluid itself in the chamber 10 would act as adiaphragm. In addition, while it may be preferable to have the chamber10 an exact number of quarter wavelengths in length, nonetheless by theintroduction of reactive elements into the chamber 10, such as adeformation orbulge in the outer wall 42, or a side chamber connected tothe outer wall 42, the actual length of the chamber 10 may be shorter orlonger than the effective length of the chamber 10 which is kept at anintegral number of quarter wavelengths in length.

Since the efficient operation of the pump requires that it be operatedin a resonant condition, it is necessary that the length of the chamber10 be maintained at an integral number of quarter wavelengthsindependent of the velocity of the wave in the fluid in the chamber 10.Thus, since the velocity of the wave in the fluid is temperaturedependent, the embodiment shown in FIG. 5 illustrates the use of atemperature sensor 48 which has a feedback path 50 coupled to the driver26. The temperature sensor 48 may, for example, be a thermocouple whichsends back a voltage dependent on the temperature of the fluid, whichvoltage serves to vary the frequency output of the driver 26 and thus toalter the frequency of the wave in the fluid such that the chamber 10remains an integral number of quarter wavelengths in length. As analternative to using such a temperature sensor, the chamber shown inFIG. 5 has also provided therein a bellows-type section 52 which servesto expand and contract depending on the temperature of the fluid in thechamber 10. In this manner as the velocity of the wave in the fluidchanges due to temperature changes, so does the length of the chamber soas to keep the length of the chamber an integral number of quarterwavelengths in length for a fixed frequency of excitation of thetransducer 18 by the driver 26.

In lieu of either of the above methods for maintaining the pump in aresonant condition, the chamber 10 itself may be used as the frequencydetermining element in an oscillator circuit. In this embodiment avoltage generated by a crystal oscillator circuit is applied to apiezoelectric crystal which is part of such circuit and which forms onewall of the chamber 10, as in FIGS. 1 or 3. The deformation of thecrystal, which is acoustically coupled to the fluid in the chamber 10,causes a wave to be propagated the length of the chamber 10 and to bereflected back to the crystal. The amount of time required for the waveto return to the crystal automatically determines the resonant frequencyof the chamber 10, and the presence of the return wave front at thecrystal causes a positive feedback therefrom which is used, as in anystandard oscillator circuit, to excite the crystal oscillator circuit toreinforce the original wave. In this manner then the entire systembehaves as an oscillator circuit with the chamber 10 acting as thefrequency determining element. If the length of chamber 10 changes orthe temperature of the fluid, and thus the velocity of propagation ofthe wave, changes, the frequency of the wave automatically changes tokeep the chamber 10 in a resonant condition. A loosely coupled frequencyranging element may be coupled to the system to limit its operation tothe fundamental frequency or the desired harmonic.

Although particular embodiments of the invention have been described andillustrated herein, it is recognized that modifications and variationsmay readily occur to those skilled in the art. Thus, for example,chamber 10 could be excited from both ends thereof by a pair ofsynchronized transducers in order to obtain a greater pressuredifferential in the nodes and antinodes. lnaddition, if the fluid to bepumped is air, one end of the chamber 10 could be left open with thechamber 10 then being an integral number of half wavelengths in length.If desired the chamber 10 could be closed at both ends and still be anintegral number of half wavelengths in length with an entrance or exitport being provided in the center and exit or entrance ports beingprovided at either or both ends thereof. Finally the chamber 10 need notbe tubular so long as it is resonant in some mode with the shape andposition of the entrance and'exit ports being determined by the positionof the nodes and antinodes of the resonant chamber. Consequently, it isintended that the claims be interpreted to cover such modifications,variations, and equivalents.

What is claimed is:

l. A pump comprising:

a chamber for receiving a fluid to be pumped;

driver means, including transducer means, for estab-' lishing travellingwaves in said fluid in said chamber, said transducer means beingpositioned within said chamber to create travelling waves on both sidesof said transducer;

means including said driver means and said chamber for converting saidtravelling waves to standing wave patterns in said fluid in said chamberon both sides of said transducer having one or more pressure nodes andone or more pressure antinodes therein;

at least one entrance port in said chamber at said pressure nodes; and

at least one exit port in said chamber at said pressure antinodes.

2. The pump of claim 1 wherein entrance and exit ports are positioned insaid chamber on both sides of said transducer means.

3. A pump comprising:

a chamber for receiving a fluid to be pumped;

driver means for establishing a travelling wave in said fluid in saidchamber;

means including said driver means and said chamber for converting saidtravelling wave to a standing wave pattern in said fluid in said chamberhaving one or more pressure nodes and one or more pressure antinodestherein, said chamber, said driver means and said aforesaid meansforming an oscillator circuit and said travelling wave generating apositive feedback in said oscillator circuit to adjust the frequency ofsaid driver means at the resonant frequency of said chamber;

at least one entrance port in said chamber at said pressure nodes; and

at least one exit port in said chamber at said pressure antinodes.

4. A pump comprising:

a chamber for receiving a fluid to be pumped;

driver means for establishing a travelling wave in said fluid in saidchamber;

means including said driver means and said chamber for converting saidtravelling wave to a standing wave pattern in said fluid in said chamberhaving one or more pressure nodes and one or more pressure antinodestherein;

at least one entrance port in said chamber at said pressure nodes, saidentrance port comprising a valveless opening in said chamber; and

at least one exit port in said chamber at said pressure antinodes.

5. The pump of claim 4 wherein said driver means includes a pair ofsynchronized transducers each one positioned at one end of said chamberto obtain a greater pressure differential in said nodes and antinodes.

6. The pump of claim 4 wherein said chamber includes a bellows-typesection operable to expand and contract with temperature variations. I

7. The pump of claim 4 wherein said driver means includes a transducerand said transducer is supported by a webbing coupled to the sides ofsaid chamber, said entrance or exit port being formed between saidtransducer and said chamber sides.

8. A pump comprising: a chamber for receiving a fluid to be pumped;driver means for establishing a travelling wave in said fluid in saidchamber; means including said driver means and said chamber forconverting said travelling wave to a standing wave pattern in said fluidin said chamber having one or more pressure nodes and one or morepressure antinodes therein;

, 3,743,446 7 8 at least one entrance port in said chamber at saidtransducer being supported by a webbing coupled pressure nodes; and tothe sides of said chamber, said entrance or exit at least one exit portin said chamber at said pressure port being formed between saidtransducer and antinodes; said chamber sides. 1

said driver means including a transducer and said

1. A pump comprising: a chamber for receiving a fluid to be pumped;driver means, including transducer means, for establishing travellingwaves in said fluid in said chamber, said transducer means beingpositioned within said chamber to create travelling waves on both sidesof said transducer; means including said driver means and said chamberfor converting said travelling waves to standing wave patterns in saidfluid in said chamber on both sides of said transducer having one ormore pressure nodes and one or more pressure antinodes therein; at leastone entrance port in said chamber at said pressure nodes; and at leastone exit port in said chamber at said pressure antinodes.
 2. The pump ofclaim 1 wherein entrance and exit ports are positioned in said chamberon both sides of said transducer means.
 3. A pump comprising: a chamberfor receiving a fluid to be pumped; driver means for establishing atravelling wave in said fluid in said chamber; means including saiddriver means and said chamber for converting said travelling wave to astanding wave pattern in said fluid in said chamber having one or morepressure nodes and one or more pressure antinodes therein, said chamber,said driver means and said aforesaid means forming an oscillator circuitand said travelling wave generating a positive feedback in saidoscillator circuit to adjust the frequency of said driver means at theresonant frequency of said chamber; at least one entrance port in saidchamber at said pressure nodes; and at least one exit port in saidchamber at said pressure antinodes.
 4. A pump comprising: a chamber forreceiving a fluid to be pumped; driver means for establishing atravelling wave in said fluid in said chamber; means including saiddriver means and said chamber for converting said travelling wave to astanding wave pattern in said fluid in said chamber having one or morepressure nodes and one or more pressure antinodes therein; at least oneentrance port in said chamber at said pressure noDes, said entrance portcomprising a valveless opening in said chamber; and at least one exitport in said chamber at said pressure antinodes.
 5. The pump of claim 4wherein said driver means includes a pair of synchronized transducerseach one positioned at one end of said chamber to obtain a greaterpressure differential in said nodes and antinodes.
 6. The pump of claim4 wherein said chamber includes a bellows-type section operable toexpand and contract with temperature variations.
 7. The pump of claim 4wherein said driver means includes a transducer and said transducer issupported by a webbing coupled to the sides of said chamber, saidentrance or exit port being formed between said transducer and saidchamber sides.
 8. A pump comprising: a chamber for receiving a fluid tobe pumped; driver means for establishing a travelling wave in said fluidin said chamber; means including said driver means and said chamber forconverting said travelling wave to a standing wave pattern in said fluidin said chamber having one or more pressure nodes and one or morepressure antinodes therein; at least one entrance port in said chamberat said pressure nodes; and at least one exit port in said chamber atsaid pressure antinodes; said driver means including a transducer andsaid transducer being supported by a webbing coupled to the sides ofsaid chamber, said entrance or exit port being formed between saidtransducer and said chamber sides.